Study of thermalization and relaxation process after ionization using attosecond pulse radiolysis

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H01374
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: Osaka University
• Principal Investigator: Yoshida Yoichi 大阪大学, 産業科学研究所, 教授 (50210729)
• Co-Investigator(Kenkyū-buntansha): 菅 晃一 大阪大学, 産業科学研究所, 助教 (60553302) ; 近藤 孝文 大阪大学, 産業科学研究所, 助教 (50336765)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 放射線化学 / 量子ビーム / ナノファブリケーション / 電子加速器 / パルスラジオリシス

Outline of Final Research Achievements

Theoretical study of ultra-short electron beam generation found the third order effect in longitudinal phase-space distribution through electron transport simulation. To realize wide range of electron bunch length measurement, electron bunch measurement systems by a Michelson interferometer with dual band detector for frequency domain measurement and by a photoconductive antenna with pulsed laser for time domain measurement were successfully developed.
Early stage processes just after ionization induced by ionizing radiation were studied in non-polar solvent and halomethanes. In non-polar solvent, it was found that the contribution of high mobility electron like quasi-free electron cannot be ignored in addition to the well-known diffusion controlled reaction. In halomethanes, the dominant reaction intermediate was not the same in ionizing radiation induced reaction with that in photo-ionization.

Free Research Field

放射線化学

Academic Significance and Societal Importance of the Research Achievements

超短パルス電子ビーム発生・測定系の構築および超高時間分解パルスラジオリシスを用いて、種々の物質で量子ビーム誘起反応の熱化・緩和過程を解明した。本研究のパルスラジオリシスを用いることにより、量子ビーム誘起反応の熱化・緩和過程の測定が可能となり、EUV（極端紫外線）等の次世代半導体微細加工では、新しいレジストプロセスの開発が可能となる。放射線がん治療において重要な放射線のDNAに与える効果として、DNAの直接イオン化や水和前電子の高速反応の寄与が指摘されており、前駆体であるドライ電子や水和前電子の反応性の解明は、放射線の生物影響の理解に大きく寄与する。